Network Topology
IN PROGRESS Network topology is the placement of various elements (links, nodes, etc.) in a computer network. In essence, it is the topographical structure of the network, which can be physically or logically represented. Physical topology is the subject of various network components, including device location and installation of cable, while the logical structure illustrates how data flows in the network, regardless of the physical design. The distances between nodes, the physical bonds, and transfer rates or signal types may vary between two networks, while still being identical topologies. Topology There are two basic types of topology, logical topology, and physical topology. Logical Topology The logical structure is the way that signals react to the network media, or the amount of data passing through the network from one device to another without regard to the physical connection of devices. The logical structure of the network is not necessarily the same as the physical topology. For example, Ethernet repeater hubs originally used a logical bus topology design, with a physical star topology. Physical Topology The wires used to connect the devices represent the physical topology of the network. This refers to the layout of the wires, and locations of the nodes and the relationship between the nodes and wires. The physical topology of a network is decided by the capabilities through access to the network and media devices, and the level of control or error tolerance required, and costs associated with circuit wiring or communication error identification. Network topology encompasses seven basic topologies: point to point, bus, star, ring or circular, mesh, tree, and hybrid. Point to Point Point-to-point is the simplest topology with a permanent link between the two endpoints. Switched point-to-point topology is the basic model of traditional telephony. The value of the network is a permanent point to point communications without obstructions between the two end points. Bus In local networks where the use of the bus topology, each node is connected to a single cable. Are connected to each computer or server to the cable and one bus. Source signal travels in both directions at all connected to the bus line until it finds the target computers. If you do not match the machine direction with the title provided for the data, and ignore the machine data. Alternatively, if the device match the address of the data, the data are accepted. Because the bus topology consists of a single wire, which is not too expensive to implement compared to other topologies. However, the compensation for the low cost of application of technology through the high cost of network management. Moreover, where is the use of only one cable, it may be a single point of failure. Star In local networks with star topology, is connected to each host on the network to the central shaft with a point-to-point connection. In a star topology is associated with each node (computer workstation or other peripherals) to a node-called axis or core switch. Transformation is the server and are marginal customers. You do not necessarily have the network to look like a star to be classified as a star network, but must be linked to all the network nodes to a central device. All traffic crossing the network passes through the central axis. The center works as a signal repeater. The topology star topology is easier to design and implement. One advantage of the star topology simply adding additional nodes. The main drawback of the star topology is that the cube represents a single point of failure. Ring Network topology is configured in the circular which data travels around the ring in one direction, and each device in the ring and duplicate work to maintain a strong signal as it travels. Each device has a GPS receiver to signal incoming and transmitter to send data to the next device in the ring. Network depends on the ability of the signal to travel around the ring. When the device sends data must travel through each device in the ring until it reaches its destination. Each node is the primary link in the ring topology, not computer server present; all nodes operate as a server and repeat the signal. The disadvantage of this topology is that if one node fails, the network is affected or completely stopped working. Mesh Meshed networks fully commensurate with the value of the exponent of the number of subscribers, assuming that groups either ends of communication, up to and including all endpoints, rounded by Reed's law. Fully connected mesh Fully connected network is a communications network that connects each node to each other. In graph theory is known as the full graph. Connected network does not require fully switch or broadcast. -A two-node network is technically fully connected network. Partially connected mesh Network topology associated with some of the network nodes to more than one other node in the network with link-point type to a point - and this makes it possible to take advantage of some of the redundancy that is provided by the network topology completely linked to the material without the expense and complexity required to connect between each node in the network. Tree Tree topology is basically a combination of bus topology and star topology. Is replaced by the decade of the bus topology with independent star topology networks. This leads to two of the disadvantages and advantages of the bus topology star topology. For example, if the network connections between the two groups decompose due to break the connection in the central nucleus of sin, then these two groups cannot communicate, and was held in a bus topology. However, the contract star topology communicates effectively with each other. Has a root node, the intermediate and final contract and the contract. This structure is arranged hierarchical manner, and can be any intermediate node, any number of the decade. But the tree topology is almost impossible to build, because the network node not only can be a computing device and at most one or two connections, so you cannot attach more than two nodes of the child to the computer (I-node or father). There are many structures smaller sub-tree topology, but it is better Tobologia- B tree to look for errors is relatively easy. There must be a network topology based on hierarchical physical at least three levels in the hierarchy of the network tree with a root 'and the central node only one hierarchical level below show the physical topology of the star. Network will be classified based on physical hierarchical topology and with branching factor of 1 as a linear topology facility. Branching factor, and, independent of the total number of nodes in the network, and therefore, if you require a network port to connect to other nodes in the number of ports per node can be kept low in spite of the total number of large contract. - And this is what makes the effect of adding the cost per node ports depends entirely, and can therefore branching factor to remain low as far as necessary, without any effect on the total number of nodes that are possible. The total number of point-to-point links in the network depending on the physical hierarchical scheme is one less than the total number of network nodes. If the nodes in the network, which is based on the topology of hierarchical material to perform any processing on the data sent between nodes in the network will require that the contract which are found in higher levels in the hierarchy of conduct further processing operations on behalf of other nodes that are lower in the sequence hierarchy. This network topology is useful, and highly recommended. An example of this network can be a cable TV technology. Other examples are based on the dynamics of the military, mining and mobile applications in various wireless networks tree. and the Naval Postgraduate School, Monterey CA, showed this type of existing trees on the border security of wireless networks. In the pilot system cameras kept aloft by balloons broadcast in real-time HD video to ground personnel through a dynamic self-healing network based on a tree. Hybrid Hybrid networks use a combination of two or more of the topology, such that the resulting network does not carry the standard topology (eg, bus, star, ring, etc.). For example, a tree network connected to the tree is still a tree network topology. Production of hybrid topology is always when they are two different basic structures of networks connected. Common examples of mixed network are: red ring of stars and bus network star Star network consists of a loop of two or more of the star topology is connected by unit access multistation (MAU) as a central hub. Star bus for two or more of the network topology consists star connected by buses trunk (trunk bus serving as the backbone of the network). While connecting lines and networks bull found popularity in high-performance computing applications, some systems have used genetic algorithms to design customized networks that have the least number of hops between different nodes. Some of the resulting designs are almost incomprehensible, but it works very well.